Text 33]
The Birth of Lord Kṛṣṇa
251
father of the Prajāpatis);  prajā-sarge —in the creation of progeny;  yadā —when;  tataḥ —thereafter;  sanniyamya —keeping under full control;  indriya-grāmam —the senses;  tepāthe —underwent;  paramam —very great;  tapaḥ —austerity.
TRANSLATION
When both of you were ordered by Lord Brahmā to create progeny, you first underwent severe austerities by controlling your senses.
PURPORT
Here is an instruction about how to use one's senses to create progeny. According to Vedic principles, before creating progeny one must fully control the senses. This control takes place through the  garbhādhāna-saṁskāra . In India there is great agitation for birth control in various mechanical ways, but birth cannot be mechanically controlled. As stated in  Bhagavad-gītā  (13.9),  janma-mṛtyu-jarā-vyādhi-duḥkha-doṣānu-darśanam : birth, death, old age and disease are certainly the primary distresses of the material world. People are trying to control birth, but they are not able to control death; and if one cannot control death, one cannot control birth either. In other words, artificially controlling birth is not any more feasible than artificially controlling death.
According to Vedic civilization, procreation should not be contrary to religious principles, and then the birthrate will be controlled. As stated in  Bhagavad-gītā  (7.11),  dharmāviruddho bhūteṣu kāmo 'smi : sex not contrary to religious principles is a representation of the Supreme Lord. People should be educated in how to give birth to good children through  saṁskāras , beginning with the  garbhādhāna-saṁskāra ; birth should not be controlled by artificial means, for this will lead to a civilization of animals. If one follows religious principles, he automatically practices birth control because if one is spiritually educated he knows that the aftereffects of sex are various types of misery ( bahu-duḥkha-bhāja ). One who is spiritually advanced does not indulge in uncontrolled sex. Therefore, instead of being forced to refrain from sex or refrain from giving birth to many children, people should be spiritually educated, and then birth control will automatically follow.